I kind like the turnfin that's For sale @ Zippkits. You can use the .21 Zip hardware on the.45 Hawk. Just another option. If your a builder then you'll be back to Zippkits. When rigger fever sets-in The Octura strut & rudder are heavy. Liter is faster 60 MPH . Did you happen to look at the .21 Zippkits [World Record] driven by Martin Truax Jr On Joe's web site. The .67- .90 are being replaced by Gas. Why cost Nitro is not cheap any more. As is glow plugs. I can eat up a gallon in one afternoon. I used 3 gallons running my .21 & .12 all season long. .45 engines are not too bad.